How to use array to create circular array without spiralling
Create an arch or an object to be repeated.



Create a closed curve (circle) This curve will control the perimeter.



On you object add an Array Modifier with the Fit Curve option and your cicle selected.
Then add a Curve Modifier using the circle again to control it.





Then add another array!



If you add an empty in the middle of the circle and use it as an offset object you can create variations in size and rotation by changing the placement, size and rotation of the empty.